Proposed Correction And Influence Of Drilling Fluids On In Situ X-Ray Fluorescence Logging

Drilling is an important method of geological survey work is the discovery and validation of concealed deposits (of) that economic, direct means. Some minerals (eg uranium) has been carrying out large-scale survey with a drill. The traditional access to drilling results, only one representation that core samples for chemical analysis. The process is: extract from the drill core, split core sampling, crushing reduced hours, for chemical analysis. X-ray fluorescence logging, that is, X-ray fluorescence analyzer probe placed deep borehole drilling or in situ determination of the target element's content or grade.Conventional X-ray fluorescence analysis of indoor and ground on-site X-ray fluorescence analysis, the measured objects are dry powder samples, or water containing a certain (generally less than 10%) of soil or rock, and placed in air or vacuum in the measurement. As the X-ray penetration depth is limited, regardless of the existence of well fluid to primary or secondary X-rays are produced X-ray absorption and scattering. Theoretical calculations show that, 15mm thick layer of water can absorb 10% of the total copper content of the Cu K-series characteristic radiation. Although the logging probe tube with a probe part of the attachment device, in X-ray fluorescence logging work, the well bore hole wall of the local change is unknown whether the detection window at the side with the wall at all measuring points in close contact state is unknown, still between the probe and the measured wall filled with a layer of well fluid. In the probe tightly to the wall under the premise of further correction gap of less than 3 mm thick layer of well fluid on the X-ray fluorescence logging results. Of fluid filled well on X-ray fluorescence thickness measurement of and propose effective correction technology to ensure in situ X-ray fluorescence analysis of the accuracy Logging, one of the key accuracy. Subject of this paper from: Geological Survey of China Geological Survey Project: "X-ray fluorescence logging technology" (item number: 1212010706501).Papers from a practical point of view, the formula derived by theoretical analysis and, combined with a large number of experimental data comparison. Logging on the X-ray fluorescence spectra measured in information extraction and calculus, to realize the impact of the introduction by the well fluid to correction. Paper made the following findings:(1) Background Subtraction Using Fourier and Gaussian fitting all-round peak demand measured spectral data pretreatment, as well liquid correction to provide a target data element of the net peak area counts.(2) Theoretical research and experimental analysis shows that: with the well fluid thickness increases, the count of excitation source scattering peaks gradually increase and approach to a certain value; target element characteristic peak counts less exponential law.(3) The probe tube and was filled with a variety of intramural Well Logging fluid case, is logging in the probe tube and the wall of pitch changes, and the multiple scattering due to an increase of radiation, beryllium window in the probe tube impurities were inspired by the characteristics of ray exposure rate increased with the well fluid thickness also increased gradually and approach to a certain value.(4) Above by the law of the analysis and experimental verification, a new spectrum measured by extracting the information in the influence of drilling fluidCorrection approach.Experimental results show: After the correction of drilling fluid and some out after the correction, logging equipment can be filled with well fluid as well as X-ray fluorescence elemental analysis device structure change, it can still achieve high and high grade mine in situ The line of accurate elemental analysis. Well within the fluid changes in the 0-3mm, the copper content of 1% copper layer lines characteristic CuKa radiation generated by the relative changes in peak area is less than 10%. The simulations show that the wall sample testing, on Fe, Cu, Zn, Pb analog wall model, except for individual models, the relative error of about 10%.